SEA LILIES, STAKFISHES, ETC. CLABK. 67 



intermediate plates, few and scattered, with 6-12 spine lets ; 

 actinolateral plates very few, small and scattered, with very 

 few spinelets. Adambulacral jjlates as wide as long, or 

 wider ; the furrow margin bears 8 or 7 (proximally), 6 or 5 

 (distally), slender, not sharp, membrane-united spines, the 

 middle ones longest, 1.5-2 mm. long ; actinal surface of plate 

 with a transverse, slightly curved series of 7-9 similar spines, 

 2-3 mm. long. Oral plates with a marginal series of 14 

 similar spines, the proximal longest and largest, 3-3.5 mm, 

 long ; actinal surface of each plate with a longitudinal series 

 of 8-10 similar spines, near inner margin. Madreporite 

 small and inconspicuous, half way between centre of disk and 

 margin. Colour (dry), dull brown ; other specimens are hght 

 yellowish -brown . 



Although all four specimens have 11 rays each, the three 

 from Tasmania are obviously different from the holotype, in 

 their hghter colour, more conspicuous skeleton, more slender 

 rays, and thinner and less noticeable membrane covering and 

 uniting the spines, both abactinally and actinally. In view 

 of the weU-known diversity in all such particulars shown by 

 the common, northern species of Crossaster (C. papposus), I 

 think there is httle reason to consider these differences of any 

 special significance, especially since the Tasmanian specimens 

 are poorly preserved. The large number, and the slenderness 

 of the adambulacral and oral spines readily distinguish the 

 present species from any of those previously known. 



Logs. — Between Gabo Island, Victoria, and Disaster Bay, 

 New South Wales, 50-100 fathoms. This specimen has been 

 selected as the holotype. 



South-east of Bruni Island, Tasmania, 150-230 fathoms. 



Genus Ptbraster, Muller and Troschel. 



Pteraster tetracanthus,! sp. nov. 



(Plate xviii., fig. 1-2.) 



R=30mm. ; r=24mm. ; R = 1.25r. General form almost 

 perfectly pentagonal, moderately thick. Abactinal surface 

 in such poor condition it is not possible to determine exactly 

 the number of paxillar spines ; paxillse somewhat numerous 

 and paxillar spines long, apparently about 6. Spiracles 



1. TeT/3a/cai/6os=having four spines; in reference to the armature of the 

 adambulacral plates. 



